Accurately measuring the elevated temperature of a remote object in a very hot environment, such as a furnace, using optical techniques and without touching the object is complicated by reflections of the environment's ambient radiation along with radiation from the heated object itself. Radiation thermometry is a technique which allows the measurement of the temperature of a remote object by analyzing the radiation emitted by the object. All objects at temperatures greater than 0 kelvin emit radiation which can be measured to determine the temperature of the object, provided the emissivity of the object is known. The concept of radiation thermometry is based upon the underlying principle that as the temperature of an object increases, the radiation it emits shifts in wavelength and increases in intensity so that an object which emits radiation with an orange glow is hotter than an otherwise identical object which emits radiation with a red glow. Details of radiation thermometry are discussed in the literature (See, for example, Tenney; Mechanical Engineering, Oct. '86; "Red Hot ... AND HOTTER", pp. 36-41.)